Glossary

Bottom Ash

The non-airborne combustion residue from burning pulverized coal in a boiler; the material which falls to the bottom of the boiler and is removed mechanically.

Cenospheres

Inert, hollow balls of sand-like material. This material is lightweight, rigid, and waterproof and is useful in a variety of products such as bowling balls, paint, concrete, and epoxy foams. TVA is removing cenospheres from the water with skimmer booms and flat barges with vacuum trucks. About 25 tons of cenospheres are floating on the river.

Coal Combustion Products (CCPs)

Materials produced primarily from the combustion of coal in coal-fired power plants.

Dike

A levee, embankment, usually earthen that can act as a barrier for containment purposes.

Dredge Cell

A unit consisting of an ash storage pond contained by a dike typically built out of ash and clay and used to receive dredged ash from a wet ash pond. Dredge cells typically are closed by covering with dirt and planted with vegetation to prevent erosion.

Dredging

Removal of settled materials from the bottom of water bodies.

Finished Water

Water that has passed through all the processes in a water treatment plant and is ready to be delivered to consumers.

Fly Ash

Fly ash is a product of burning finely ground coal in a boiler to produce electricity and is stored in containment areas often called ash ponds. Physically, fly ash is a very fine, powdery material; composed mostly of silica nearly all particles are spherical in shape. This gives fly ash a consistency somewhat like talcum powder. Because of its shape and properties, fly ash is useful in cement and concrete applications.

Ground Water

The supply of water found beneath the Earth's surface which supply wells and springs.

Headwater

The source of a river or stream or place from which the water in a river or stream originates.

The U.S. Environmental Protection Agency (EPA) has established nationwide enforceable standards for certain constituents of drinking water that are believed to pose certain health risks. These numbers are called MCLs and are the maximum permissible level of a contaminant in water which is delivered to any user of a public water system. MCLGs are the level of a contaminant below which there are no known or anticipated adverse health effects, and which allow an adequate margin of safety.

Micrograms per Liter (ug/L)

Similar to the description of Milligram per Liter below, 1 microgram per liter (ug/L) is equivalent to 1 part per billion parts, or 1 ppb by weight.

Milligrams per Liter (mg/L)

Standard unit of measure for reporting the concentration of constituents in water. A milligram (mg) is one-millionth of a kilogram (kg). One liter of water weighs approximately 1 kg. Therefore, one milligram is one-millionth of the mass of 1 liter of water (I kg), and equals 1 part per million parts, or 1 ppm by weight.

Primary Drinking Water Standards

Standards identified by the EPA for a number of constituents with associated health risks. These are legally enforceable standards that apply to public water systems and are designed to protect the public from ingesting potentially toxic levels of chemicals. The following metals can be found on this list and have been requested for analyses of residential well samples submitted by TDEC. Antimony (Sb), Arsenic (As), Barium (Ba), Beryllium (Be), Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Mercury (Hg), Selenium (Se), and Thallium (Th).

Raw Water

Untreated water extracted from groundwater, dams, or rivers that has not been treated.

Secondary Drinking Water Standards

Standards that EPA has identified for drinking water constituents that may cause cosmetic (skin or tooth discoloration) or aesthetic effects (such as taste, color or odor) in drinking water. For these constituents, EPA has established unenforceable guidelines that may or may not be adopted by individual states as enforceable standards. Metals listed in this category by the EPA are: Aluminum (Al), Copper (Cu) [both lists], Iron (Fe), Manganese (Mn), Silver (Ag), and Zinc (Zn).

Sludge

Sludge is the muddy waste that is produced during processes to remove sulfur from coal.